# A dual mode approach based efficient relay-aided device-to-device communication in 5G mm-Wave cellular network

## TL;DR

This paper proposes a dual mode communication system using relays to improve performance in 5G mm-Wave networks.

## Contribution

A novel dual mode (direct and relay) communication scheme is introduced to enhance spectral and energy efficiency in 5G mm-Wave networks.

## Key findings

- The relay mode outperforms the direct mode in terms of spectral and energy efficiency.
- Energy efficiency increases to around 180 Mbps/J with higher D2D transmit power.
- The average data rate reaches 135 Kbps at 250 mW D2D power with pathloss attenuation of 2.5.

## Abstract

Relay aided device-to-device (D2D) communication has the potential to increase the capacity and coverage of the network thereby enhancing the quality of service (QoS). Thus, we propose a dual mode scheme (direct and relay mode) for a single cell where D2D and cellular users co-exist in an underlaying 5G mm-Wave cellular network which minimizes the interference. Direct mode operates at 2 GHz carrier frequency while relay mode employs full duplex amplify and forward (FDAF) relay strategy at 28 GHz frequency. The closed form expressions of performance metrices namely, spectral efficiency (SE) and energy efficiency (EE) are derived using stochastic geometry as a tool for both the modes to evaluate the system performance. Expressions for probability distribution function (PDF) and cumulative distribution function (CDF) are also derived. Simulation results suggest that the relay mode exhibits better performance than the direct mode in terms of SE and EE. With an increase in the D2D transmit power; the EE gradually increases to around 180 Mbps/J. The average data rate also increases to around 135 Kbps at D2D power of 250 mW with pathloss attenuation of 2.5. Further, simulation results validate the efficacy of the proposed scheme. Also, comparison of the proposed method with the existing methods depicts better performance of the proposed system.